1. Field of the Invention
The present invention relates to the use of a natural preservative such as Natamycin in combination with chemical preservatives such as sorbates, benzoates and the like in aqueous based beverages containing tea solids which under some conditions are subject to yeast and mold outgrowth.
2. Related Art
Natamycin, also known as pimaricin, is an antifungal agent produced by Streptomyces natalensis. The compound is effective against yeasts and molds and is reported to be ineffective against bacteria. It is approved for use as an additive which may be applied to the surface of cuts and slices of cheese to inhibit mold spoilage (21 CFR 172.155). This information is available from an article on "Antimicrobials: Assuring Food Safety" by J. Giese in the June 1994 Food Technology periodical 48 (6) pp. 101-110.
Natamycin has been used in animal feeds U.S. Pat. No. 4,600,706, in sausages and sausage casings U.S. Pat. No. 4,664,861 and in mixtures with other preservatives to preserve milk U.S. Pat. No. 5,196,344.
Generally, however, the solubility of Natamycin has limited its use to the surface treatment of cheese for which it is approved by the FDA.
Natamycin has also been of interest in the treatment of food products because it is highly active against yeasts and molds, as opposed to bacteria (see Morris and Hart, "Pimaricin--What is It?", Culture Dairy Products Journal, Volume 13, page 22, 1978.) Reportedly, Natamycin has been applied to food products in several ways. It has been added in dry form to liquids, slurries, pastes and semisolids when adequate mixing can be accomplished, or the pure Natamycin can be mixed with one or more of the dry ingredients and then added to a given food product. Solid foods requiring surface protection can be dipped, misted, fogged or dusted with a solution or suspension of Natamycin. Additionally, it has been suggested that protection from yeast and molds may be achieved in solid food by incorporating Natamycin homogeneously into the food itself.
Natamycin has also been used to retard spoilage of dressed poultry, to protect cottage cheese, and has been widely used in the dip-treatment of cheeses to coat them with the fungicide which is absorbed slightly, and dries to form a solid, surface coating. Various other reports suggest that Natamycin is effective in the treatment of fresh berries, tomatoes, strawberries and raspberries. These reports indicate that Natamycin has an antiyeast activity when added to wines, and various fruit juices, such as apple juice or orange juice. (See, Morris and Hart, cited above.)